Apparatus for the recovery of solvents from coated fabrics



July 31, 1928.

H. S. THOMPSON APPARATUS FOR THE RECOVERY OF SOLVENTS FROM COATED FABRICS 5 Sheets Sheet 1 Filed Feb. 1'7, 1927 Nml July 31, 1928.

H. S. THOMPSON APPARATUS FOR THE RECOVERY OF SOLVENTS FROM COATED FABRICS 5 Sheets-Sheet 2 Filed Feb. 17, 1927 n l C U 0 W AU W F W n F r O obobgohvb pDDDOpUgE gnvgog 0 one 0!. one c: oi. 0K0 on. all on. on. on. 0%. in 0 n 0! x .1 O 9m OHU . Ho 0H0 ouoono ouo ouoouo one Q0 Q0 OHUAHO July 31, 1928. 1,678,886

H. s. THOMPSON APPARATUS FOR THE RECOVERY OF SOLVENTS FRQI COATED-FABRICS Filed Feb.1'7, 1927 '5 Sheets-Sheet 6 zia r/ei itor 2 x22. W-m- 83.8 v v /7? "7 7 A Patented July 31, 192 8.

HERBERT S. THOMPSON, OF PEEKSKILL, NEW YORK.

APPARATUS FOR THE RECOVERY OF SOLVENTS FROM COATED FABRICS.

Application filed February 17, 1927. Serial No. 169,119.

The present invention relates to apparatus for the recovery of solvents from coated fabrics.

The object of the invention is to provide a novel and improved apparatus for drying, and recovering solvents from coated fabrics which will operate rapidly and efficiently and in which the possibility of explosion during the drying and recovery process 1s practically or entirely eliminated.

In carrying out the invention, a single closed chamber is provided in which the come rapidly concentrated in the chamber until they reach a high density, practically displacing the air so that durlng the continued operation of the apparatus there 1s not a sufficient percentage of oxygen for the propagation of an explosive wave. To condense the solvent vapor a number of condensers are provided and in order to permit and create a free and rapid circulation of the vapor to bring it in contact or within the influence of the condensers the supports for the web and heating devices are arranged to leave the chamber otherwise substantially unobstructed, and the condensers are located adjacent the walls of the chamber at the sides of the web and are arranged to create a circulation of the vapor across the web fromv one edge towards the other and down one side, across the bottom and up the opposite side of the chamber.

The invention contemplates leading the web through the chamber in any suitable manner, but preferably the web is led in a horizontal direction and passes back and forth within the chamber a number of times so that the web presents a plurality of horizontal passes to the heating devices. passing the web back and forth a number of times a sufficient extent of web surface is exposed in the chamber to permit the chamber to-be filled quickly with a. dense vapor and this density to be maintained during the operation of the apparatus even when the web is fed through the apparatus at a comparatively high rate of speed.

An apparatus embodying the invention may be used to dry and recover the solvents from a fabric provided with a single coating. A feature of the invention, however, contemplates applying a second coatino to the fabric after the first coating has con dried and in leading the web with the second coating again through the chamber so that the coats which have been applied successive- 1y to the fabric are dried in the same chamber simultaneously.

Other features of the invention will be apparent to those skilled in the art from the following description taken in connection with the accompanying drawings in which Fig. 1 is a view in side elevation of a portion of the apparatus illustrating particularly the manner in which the fabric is coated and led into and out of the machine;

Fig. 2 is a continuation of Fi 1, illustrating the remainder of the mac inc and particularly the drying and condensing chamber; and Fig. 3 is a view taken on the line 33 of Fig. 2.

The fabric is indicated at 4 and the drying and condensing chamber at 6. The fabric is drawn from a supply reel 8 over aseries of rollers and spreader bars under the two coating knives 10 and 12 of the first mill and from there through a slot into the drying chamber. Heating units consisting of a series of steam pipes 14 are mounted in close proximity to the path of the fabric through the chamber on both sides of the material to drive off the solvents from and dry the coating. The fabric is carried on tenter needle chains over the needle chain drums 16 and 18 at the further end ofv the chamber back to the drum 20 and then to the drum 22 in such a manner that for the first three passes back and forth the supporting drums come in contact only with the untreated face of the fabric so that the coating may be sufliciently dried to prevent picking off or marking before its coated face is brought into contact with the supporting drums or rollers.

Tenter needle chains, the guide rails for which are indicated at 24, are provided to engage the edges of the fabric and to stretch and hold it in extended position between the heating units during the drying of the first coat. The guide rails 24 for the chains are mounted on frames 28 adapted to move transversely ofthe web to adjust the tenter needle chains to the width of the cloth. The frames 28 may be conveniently, simultane-v ously adjusted to the desired width by means of. screws 30 threaded to the frames so that by rotating the screws in one direction the chains will be brought toward each other and by-r'otating the screws in the other direction the chalns will be spread apart.

The dried fabric is now led through a slot out of the chamber over a series of idle and slack compensating or take-up rollers ineluding the compensating floating roller 31 to the second mill comprising the two coating knives 32 and 34 and is then again assed through a slot into the drying chamer. During this second passage through the drying chamber the web passes over heating units consisting of a series of steam pipes or plates35, which pipes or plates are arranged in an arc to support the web and hold it extended as-indicated in Fig. 2. At

this stage of the process the use of tenter needles and chains to hold the coated fabric extended is unnecessary. During its'second passage, the web follows a path of the same general form as before so that three complete passes are made back and forth before the treated side of the fabric is brought into contact With the supporting rollers. The

finished fabric is then delivered from the chamber through a slot and is wound on the automatic winder indicated at 36 in Fig. 1.

It is of particular importance that an even pull and tension be exerted on theweb "from the time it leaves the reel until the coating and drying processes are completed and it is wound up on the automatic winder 36. To this end the two operating sections of the machine and the winder have been constructed and synchronized so as to exert an even pull and tension on the goods throughout the coating and drying opera tion and a compensating floating roller 31 has been provided to take up any slack and to equalize the tension on the fabric between the first and the second coatingand drying operations.

. The drying and condensing chamber 6 is provided with a V-shaped lower-portion run ning and pitched lengthwise of the chamber to collect the solvents condensed on the cooling' coils along the sides-and bottom and-to facilitate the circulation of vaporthrough' the chamber, and the roof is sloped slightly I) to one side to enable any condensate to drain off without dropping on and spotting the. fabric.

The exterior of the chamber is covered with asbestos board or plaster to retain the'heat arid to'reduce' to. aminimuni the efi'ects' of the outside atmosphere and is" closed except for the narrow slots or openings through which the fabric. passes into and out of the chamber so that practically no oxygen from entering the chamber in sulfi-' cient quantity to create an explosive mixture. Blow holes in the top and sides covered with a thin non-porous material such as tin foil and loose air tight covers on top,

as barely indicatedat 37, are provided to release the pressure should an explosion occur, without damaging the apparatus or injuring' the operators.

The condensing coils, indicated at 38, are mountedon the V-shaped lower portion of the chamber and on the sides, the coils on the left hand side as viewed in Fig. 3 being carried higher than on the other side to cause a most eificientcirculation of vapor in the chamber.

In operation, the highly concentrated vapors of the evaporated solvents, driven'ofl from the coating by the heating coils within the chamber, come into. contact with the higher condensing coils on the left hand side and start to condense. The gas in immediate contact with the condensing coils at once contracts in volume forming a. partial vacuum into which is drawn more hot gas given off by the goods. The comparatively 'cold partially condensed gases follow down the side of the chamber across the V-shaped lower portion and up the opposite side, being at all times subjected to the action of the condensing coils lining these portions of the chamber. Finally the gas, much rarified by prolonged contact with the condensing coils, is drawn across the heating elements again to complete the cycle. In this manner a natural circulation is'set up Within the aid of forced circulation by mechanical means such as a fan'or by a heated column of air or gas. This circulation is further facilitated by the fact that the space or area between the ends of the heating coils and the condensing coils along the wall on the left hand side of the apparatus, as viewed in Fig. 3, is greater than at the opposite wall,

as is clearly shown in the figure.

Owing to the large surface of the fabric exposed'to the heating coils, the chamber is quickly charged with a high density-gas and y reason of the arrangement of the condenserand the absence of baflles or.other obstructions' in the chamber, a rapid cii'culation and condensation is set up. .Therapid cooling and condensing of the vapors driven off from the fabric greatly accelerates the drying of the fabric and furthermore reduces the pressure within the chambee so far that no danger of an explosion can, a

from this source. 7

With the present construction and arrangement of the parts it has been found possible to greatly accelerate the speed at which the web may be fed through the cham- Moreover, the efficiency of the drying and condensing process is such that a very large percentage of the solvent materials used are recovered. These solvents have the same chemical analysis as they had before use and may be used over again thus conducing still further to the efficient and economical operation of the machine.

The nature and scope of the invention having been indicated, and an embodiment of the invention having been specifically described, what is claimed is:

1. Apparatus for recovering solvents from coated fabrics, comprising a closed chamber, means for leading a coated Web through the chamber, means for heating the web, and condensers adjacent the walls of the chamber at the sides of the web arranged to create a circulation of thevapor driven .from the Webcoating across the web from one side of the web to the other and down one side, across the bottom and up the opposite side of the chamber.

2. Apparatus for recovering solvents from coated fabrics, comprising a closed chamber having a substantially unobstructed interior, means for leadingthe web back and forth within the chamber inaplurality of horizontal passes, means for heating the web and condensers adjacent the walls of the chamber at the sides ofthe webarranged to create a circulation of the vapor driven from the Web coating across the Web from one side of the web to the other and down one side, across the bottom and up the'opposite side of the chamber 3. Apparatus for recovering solvents from coated fabrics, comprising a closed chamber, means for leading a coated Web through the chamber, means for heating the web and condense-rs arranged adjacent the walls of the chamber, the condensers on one side of the chamber being arranged at a higher elevation than on the other side to create a circulation of the vapor driven from the web coating across the web from one side of the web to. the other and down one side, across the bottom and up the opposite side of the chamber. I i

4. Apparatus for recovering solvents from coated fabrics, comprising a closed chamber with a substantially unobstructed interior supporting means for leading the web back d forth in the chaniber for at least three passes without bringing its coated sideinto contact with the supporting means, means for heating the web and condensers adjacent.

the walls of'the chamber at the sides of the web arranged to create a circulation of the vapor driven from the web coatlng across the web from one side of the web to the other and down one side, across the bottom and up the opposite side of the chamber.

5. Apparatus for recovering solvents from coated fabrics to which two coats are applied successively, comprising a closed chamber, means for leading the coated web through the chamber to dry the first coat before the application of the second coat and simultaneously to dry the second coat, means for heating the web and condensers adjacent the walls of the chamber at the sides of the web arranged to create a circulation of the vapor driven from the web coating Within the chamber.

6. Apparatus for recovering solvents from coated fabrics to which two coats are applied successively, comprising a closed chamber, means for leading the coated web through the chamber to dry the first coat be fore the application of the second coat and simultaneously to dry the second coat, and condensers adjacent the walls of the chamber at the sides of the web arranged to create a circulation of the vapor driven from the web coating within the chamber.

7. Apparatus for recovering solvents from coated fabrics, comprising a closed chamber,

parallel tenter needle carrying chains n for supporting the fabric at its edges, and to stretch and hold it in extended position,

heating devices for drying the fabric and condensers adjacent the walls of the chamber at the sides of the web arranged to create a circulation of the vapor driven from the web coating across'the web from one side of the web to the other and down one side, across the bottom and up the opposite side of the chamber.

8. Apparatus for recovering solvents from coated fabrics, comprising a closed chamber having a substantially unobstructed interior, means for leading a coated web through the chamber, means for heating the web and condensers adjacent the walls of the chamber at the'sides of the web arranged to cre-.

ate a circulation of the vapor driven from the web coating across the web from one side of the web to the other and down one side, across the bottom and up the opposite side of the chamber. T

9. Apparatus for recovering solvents from coated fabrics comprising a closed chamber having a substantially unobstructed interior with a V-shaped lower portion, means for leading a coated web through the chamber, means for heating the web and condensers arranged adjacent the walls and V- shaped lower portion of the chamber, the condensers on one side of the'chamber being arranged .at a higher elevation than those'on the other side to create a circulation of the vapor driven from the Web coating .across the web fromone side of the web to the other and down oneside, across the V- liit) shaped lower portion of the chamber, and up the opposite side.

10. Apparatus for recovering solvents from coated fabrics to which two coats are applied successively, comprising a closed chamber, operating means for leading the coated web'through the chamber to dry the first coat before the application of the second coat, operating means for leading the Web again through the chamber to dry the second coat simultaneously with the first coat, and means for maintaining a constant tension at all times upon the web.

11. Apparatus for recovering solvents from coated fabrics to which two coats are applied successively, comprising a closed chamber, operating means for leading the coated Web through the chamber to dry the first coat before the application of the second coat, operating means for leading the Web again through the chamber to dry the second coat simultaneously with the first coat, a Winding reel, and means including a compensating floating roller operating upon the web between the first and second operating means for maintaining a constant tension at all times upon the web.

In testimony whereof I have signed my name to this specification.

HERBERT S. THOMPSON. 

